Thermal cautery surgical forceps

ABSTRACT

A portable, thermal cauterizing forceps device for use in surgery. The device incorporates a pair of ceramic heater elements mounted within the tips of the tines of a forceps. The forceps is used to grasp tissue or blood vessels and apply heat to effect cauterization. The forceps instrument can incorporate a battery and control electronics. The thermal-forceps is of a self-contained wireless, handheld disposable design. The forceps handpiece can be connected to an external power source. The forceps can incorporate a set of rapidly heating ceramic heater elements that may be composed of silicon nitride. An LED provides the operator feedback as to the operating level of the heaters and/or battery reserve. The forceps can include a rechargeable power supply, variable control of the heater temperature, as well as a, digital display of the tip temperature.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityunder 35 USC 120 from U.S. application Ser. No. 14/061,452, filed Oct.23, 2013 which is a continuation of U.S. application Ser. No.13/791,156, filed Mar. 8, 2013, which is a continuation of U.S.application Ser. No. 13/339,408, filed Dec. 29, 2011, now U.S. Pat. No.8,409,199, issued on Apr. 2, 2013, which is a divisional of U.S.application Ser. No. 12/577,531, filed Oct. 12, 2009, now issued as U.S.Pat. No. 8,128,623, issued on Mar. 6, 2012, which is a continuation ofU.S. application Ser. No. 11/512,159, filed Aug. 30, 2006, the entirecontents of each of which are incorporated herein by reference. U.S.application Ser. No. 11/512,159, filed Aug. 30, 2006, is a continuationof U.S. application Ser. No. 10/326,387, filed Dec. 23, 2002, which is acontinuation of U.S. application Ser. No. 09/842,140 (now U.S. Pat. No.6,533,778, issued Mar. 18, 2003), which is a continuation of U.S.application Ser. No. 09/235,229, filed Jan. 21, 1999 (now U.S. Pat. No.6,235,027, issued May 22, 2001).

BACKGROUND OF THE INVENTION

The present invention relates to a handheld, portablethermal-cauterizing forceps including an integrated thermal heatingsurface disposed at each tip.

There are many surgical cautery devices available for the surgeon toablate and vaporize tissue. Hot knives and cutting coagulators have beenused to make skin incisions. The cautery can also be used in surgery toaid in hemostasis or control bleeding by coagulating blood vessels.Employing various cautery modalities decreases the duration of somesurgical procedures by providing the surgeon a rapid method ofcoagulation without the need for suture ligation of blood vesselsencountered during dissection.

Typically, surgical cautery is accomplished by directing a heatingprocess onto tissue. The heat may be generated by either a thermal orelectro-surgical process. Most commonly, an electro-surgical processusing a radio frequency (RF) is used. The RF units generate heat byusing high frequency electrical current and the resistive nature oftissue to produce heat. This technique requires a bulky generator andheavy electrical components to operate. Typically, RF electrocauteryunits require a power lead cable to the electro-surgical hand instrumentand a large surface area grounding pad. More often than not, radiofrequency surgical units are bulky expensive units which require a cableconnection. Employing RF cauterization in a surgical operation may addsignificant cost to the procedure because the grounding pad, cable andhandpiece must all be either re-sterilized or replaced in the case ofdisposable use.

A less common method of generating heat for coagulation of tissue is bythermal cautery. Thermal cautery is achieved by electrical heating of aresistive-wire loop or resistible electronic part by applying anelectrical voltage. The prior art describes many handheld disposable,hot-wire loop cautery instruments. These devices have severe limitationsas to their scope of use in surgery. The heat generated by the handheldbattery powered devices is very small with a low heat capacity. Theavailable patented devices are effective for cauterization of only thesmallest of blood vessels, such as, vessels in the sclera of the eye.These battery powered hot-wire cautery instruments are not effective foruse in cauterization of larger blood vessels encountered in mostsurgical procedures. A technique employing the electrical over drivingof a zener diodes to produce heat has also been described in severalpatents. This device is primarily for limited endoscopic applications.

SUMMARY OF THE INVENTION

In order to overcome the limitations and disadvantages of the prior art,the present invention provides, in an embodiment, a new and improvedhand-held, high energy, portable thermal cautery forceps. Moreparticularly, the new and improved surgical forceps instrument includesan enclosure which houses a battery and electronic control. Activeceramic heaters are provided on the two tips of the operative end of theforceps. In a second embodiment, the thermal forceps may alternativelybe powered by an external power source.

The new thermo-cautery forceps device in accordance with an embodimentof the invention provides the surgeon with several significantimprovements in the state of the art. A first benefit of thethermal-cautery forceps is that it is cordless and fully portable. Inthe first embodiment of the invention, no cables or external powersupply is necessary. This keeps the operative field clear of wires andcables. The thermal cautery of this invention does not require anygrounding pad or foot switches.

A second benefit is the very high heating capacity of the thermalelements of the device. Temperatures of over 1000.degree.C. are easilyobtainable. This heat capacity and temperature can easily cauterizemedium and large blood vessels.

A third benefit provided by the new and improved thermal cautery forcepsof the invention is its ability to heat to operating temperature in avery short time period, for example, within about one second. Thepreferred embodiment uses silicon nitride, ceramic heater elements.These new ceramic heaters exhibit rapid heating and coolingcharacteristics. Silicon nitride ceramic heaters have been usedsuccessfully in other fields outside surgery. To the inventor'sknowledge, this is believed to be the first use within the field ofsurgical thermal coagulation.

In an alternative embodiment, less expensive alumina heaters and ceramicresistors or diodes may be employed in substitution for the siliconnitride ceramic heater elements to provide cost savings. However, suchalternative types of heaters may be less preferred because longer timesto obtain operating temperatures may be required.

A fourth advantage provided by the new and improved forceps is theplacement of the thermal cautery heater elements at the ends of forcepstines. The unique position of the ceramic heater elements allows tissueand blood vessels to be easily grasped and directly coagulated in acontrolled manner. The application of a closing or gripping pressure ofthe forceps against the tissue or vessel enhances the effectiveness ofthe coagulation.

A fifth benefit of the forceps device in accordance with the inventionis to decrease the cost and enhance the availability of surgicalcautery. The first embodiment of the thermal forceps allows for thedevice to be packaged as a sterile disposable instrument The instrumentcan be used in emergency or field operations. The device may be used forhemostasis during outpatient surgical procedures in clinics and insurgery centers, as well as, at emergency scenes.

Other objects and advantages provided by the present invention willbecome apparent from the following Detailed Description taken inconjunction with the Drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the new and improved thermalcautery forceps instrument of the present invention in accordance with afirst embodiment including an internal battery;

FIG. 2 is a top plan view of the new and improved thermal cauteryforceps shown in FIG. 1;

FIG. 3 is an end elevational view of the new and improved thermalcautery forceps showing the front or forceps tines end;

FIG. 4 is an end elevational view of the new and improved thermalcautery forceps viewed from the rear or opposite end of the forceps;

FIG. 5 is an elevated cross-sectional view of the new and improvedthermal cautery forceps shown in FIGS. 1-4, showing the logic controllerboard, LED indicator lamp, internal switch and internal battery;

FIG. 6 is a schematic block diagram of the electrical circuit for thenew and improved thermal cautery forceps of the first embodiment of theinvention comprising a battery powered portable device;

FIG. 7 is an elevated side view of the thermal cautery forcepsinstrument in accordance with a second embodiment of the inventionincluding an external power supply unit;

FIG. 8 is a top plan view of the new and improved thermal cauteryforceps shown in FIG. 7;

FIG. 9 is an elevated end view of the new and improved thermal cauteryforceps of FIG. 7 taken from the forceps tine end;

FIG. 10 is an elevated end view of the new and improved thermal cauteryforceps shown in FIG. 7, taken from the opposite end and showing thecable connector;

FIG. 11 is an elevated cross-sectional view of the new and improvedthermal cautery forceps in accordance with the second embodiment,showing the housing and cable connection to the pair of heater units;

FIG. 12 is an elevated front view of the external power supply unit foruse with the new and improved thermal cautery forceps in accordance withthe second embodiment showing control features, including a powerswitch, audio speaker, temperature display, SET/READ switch, temperaturecontrol knob, recharging lamp and ready LED lamp.

FIG. 13 is a perspective view of a holster for carrying a portablethermal cautery forceps made in accordance with one embodiment of thepresent invention; and

FIG. 14 is a side elevational view of the holster shown in FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with a preferred embodiment of the invention, a new andimproved thermocautery surgical forceps comprises a surgical forcepsbody including a pair of elongate tine members extending from theforceps body to respective free end tip portions spaced from the forcepsbody. The tine members are mounted to the forceps body in a mannerproviding resilient compressible movement of the tine members between anormally open position, wherein the tines are disposed in aligned,parallel, spaced-apart relationship, and a squeezed closed position,wherein the tip portions of the tine members are disposed in confrontingabutting relationship. Each tine member includes a tissue contactsurface defined on an inner facing surface of the tine member adjacentthe tip portion. A ceramic heater element is disposed in each tinemember so as to effectively heat the tissue contact surface to anelevated tissue cauterizing temperature. The ceramic heater elements areoptionally connected to a power source. The tine members may be squeezedtogether to their squeezed closed position to grippingly, squeezablyengage tissue to be cauterized between the tip portions. The tissuecontact surfaces on the tines may be heated to a tissue cauterizingtemperature to effectively thermocauterize the gripped tissue.

Referring now to FIGS. 1-6, a preferred embodiment of the new andimproved thermocautery surgical forceps Generally designated byreference numeral 10 is shown. Forceps 10 includes a forceps body orhousing 12 for the battery 14 and electrical control components 16.Specialized ceramic heating elements 18 are disposed on the tips 20 ofthe forceps tines 22, 24. FIGS. 1-6 relate to the first embodiment ofthe invention, that of a portable unit 10 with an internal batterysupply 14. FIGS. 7-12 relate to the second embodiment of the invention,that of a cautery unit 26 configured as a thermal forceps 28 and anexternal power supply 30.

As shown in FIG. 1, the first embodiment of the cauterizing instrument10 generally comprises a housing 12 and an integrated forceps tinesassembly 32. The housing 12 encloses the battery 14, controllerelectronics 34, an LED 36 and an internal power switch 38. The forcepstines 22, 24 of the instrument, as shown in FIG. 1, exit from openingsin the front end of the housing 12. The forceps assembly comprises twotines 22, 24 of equal length. Each tine 22, 24 is constructed of aheater-carrier 40 and an insulator cover-piece 42. The heater-carrier 40comprises a metal arm 44 that supports an attached ceramic heater unit46. The insulator cover-piece 42 is a shroud 48 that covers the heater46 and its carrier arm 44. The shroud cover 48 is heat resistant andprotects the surgeon's fingers from the heat generated by the ceramicheaters 46. The shroud 48 includes a recess 50 to fit the operatorsthumb and index finger to aid in holding the instrument. Inwardcompression on the shrouds 48 acts to compress the heater carrier arms44 and will cause the switch 38 to close.

FIG. 2 shows a top view of the instruments with the LED exiting the rearof the housing enclosure and the forceps shroud cover with fingerrecess. The enclosure is rectangular in shape having a closed end and anopen end. The open end allows the forceps assembly to exit from theenclosure. The enclosure is composed of a plastic formed with aninjection process. The open end of the enclosure is shown in FIG. 3. Theforceps are shown as well as the LED on the top of the housing. Theposition of the LED allows the surgeon easily visualize the operation ofthe instrument. The surgeon can see the LED while it is held in the handand operated. FIG. 4 shows the closed end of the housing.

Shown in FIG. 5 is a cross-sectional view of the enclosure containing abattery for power supply. The battery may be rated form 3 volts to 24VDC depending on the heating characteristics required. The battery maybe of an alkaline or lithium cell. The battery positive and negativeterminals are connected to the instrument circuitry by a terminalbattery clip. Also, contained within the enclosure is a small circuitboard that is populated with an integrated circuit and supportcomponents. The circuit board has connections to the power supply, LED,heater elements and switch mechanism. This circuit acts as alogic-controller to regulate the current delivered to the heatingelements. The logic-controller circuit monitors the temperature andresistance of the heater elements and regulates the voltage supply. Atthe onset of operation the logic circuit allows high current to flow tothe heaters aiding in initial rapid heating. The current is then reducedto maintain the heaters at a set temperature. The controller circuitlogic also controls the LED to indicate the operative state of theheater elements. The LED will illuminate only if the battery powerreserve or supply voltage attain a specified level and heaters reach thepreset operational temperature. The logic controller also measures theinternal resistance and temperature of the heater elements. The LED willfail to illuminate if these values fall outside the normal operationallimits.

In an alternative design of the first embodiment a small piezoelectricspeaker may be incorporated into the forceps enclosure. In thealternative design (not shown) the logic controller is further able tosupply a piezo-electric speaker with supply voltage. The piezo-electricspeaker provides the operator with auditory feedback pertaining to theoperation of the instrument. The speaker emits a sound to give thesurgeon an audio feedback as to the operation of the instrument. Thesound indicates that the heating elements are at the normal operativetemperature for effective cauterization.

Also shown in FIG. 5, is the mounting arrangement of the forceps tines.Each tine is mounted on opposite sides of a rectangular neoprene spacer.The pair of tines and neoprene spacer are fasted together by a bindingpin with end caps. The off-center arrangement fastening of the tines tothe neoprene spacer allows for a spring like tweezer effect.

An electrical open/close single pole switch is incorporated into theinstrument. The switch is positioned within the housing enclosurebetween the base of the forceps tines. The switch is composed of twocontacts that are brought into contact when the forceps are squeezedtogether. Closing the switch allows current to be delivered to theheaters. The contacts meet, as soon as, closure of the tines is begunand stays in a closed position as long as the tines are closed. Releaseof the forceps tines will open the switch and current supply to theheaters will terminate.

The typical wiring diagram and schematic is shown in FIG. 6. Theschematic shows a DC battery with positive and negative leads connectedto a logic control circuit board. The circuit board is able to regulatethe current delivered to the heater elements by measuring the internalelectrical resistance of the heaters and the voltage available from thebatteries. The controller also will vary the initial resistance of theheater circuit to obtain quick heat up at power on. The controller logicalso controls the illumination of the LED. The LED is switched on when apreset temperature of the heaters is reached. The ON/OFF switchincorporated into the forceps is also depicted. The switch is closedupon closure of the forceps and allows a current to flow to the heaters.Two heaters are shown which are wired in parallel. The internalresistance of the heaters is about 5 to 10 ohms. The typical heater iscomposed of either alumina of silicon nitride or similar glass orceramic material. This material specification is used due to highwattage density, rapid heat increase to 1000 degrees within one second,high level of insulation and non-stick nature of the ceramic to charredtissue.

The second embodiment of the invention is shown in FIGS. 7-12. In thisembodiment an external power source is used to power and control asimple thermal cautery forceps. The forceps in this embodiment is eitherof an inexpensive disposable or a more durable reusable design. FIGS. 7,8, 10 and 11 show the externally powered cautery forceps. FIG. 7 is aside elevational view of the thermal cautery forceps instrument of thesecond embodiment of the invention. A cable connects the forceps to theexternal power supply unit is shown. As previously describe is the pairof forceps exiting from an enclosure. Each tine is composed of a rigidmetal carrier with ceramic heater and an insulating plastic shroud. FIG.8 is a top plan view thereof; FIG. 9 is an end elevational view there ofillustrating the forceps tine end. FIG. 10 is an end elevational view ofthe end opposite the forceps illustrating the cable connector. FIG. 11is a cross-sectional view of the second embodiment of the presentinvention, showing the housing and cable connection. A pair of wiresconnects the cable to a pair of thermal heater elements wire inparallel. Also shown in FIG. 11 is the neoprene spacer. The spacer ispositioned between the forceps tines. An off center-binding pin throughthe tines and spacer provides a spring effect. The spring effect alsoactivates the ON/OFF switch. The switch is composed of two electricalmetal contacts affixed to the inside of each forceps tine.

FIG. 12 is a front elevation of the external power supply unit. Thisunit contains a power switch, audio speaker, digital temperaturedisplay, SET/READ switch, temperature control knob, recharging indicatorlamp and ready LED lamp.

As shown in FIG. 12, a cable that connects to the forceps enters thepower unit. A power switch is located on the front panel thatilluminates when switch on. The external unit contains an audioamplifier with a small piezo-electric speaker. The speaker signals thesurgeon of proper heater element temperature for cauterization. Thespeaker will sound when the instrument reaches the SET temperature afterthe forceps are squeezed together to initiate heating. The output of thespeaker is vented outside the power unit through a small port shown inFIG. 12. The unit also contains a temperature control. The temperaturemay be varied by positioning the SET/READ switch to the SET position androtating the temperature adjust knob to the desired temperature. Thedigital temperature display reports the desired set temperature indegrees fahrenheit. The temperature adjust control may either be of ananalogue or digital type. This control allows the surgeon to select atemperature for a desired effect depending on the thickness and moisturecontent of the tissue to be cauterized. A digital temperature displaymay indicate the actual temperature of the ceramic heater elements whenthe SET/READ switch is positioned in the READ position. An LED indicatoris incorporated into the power supply, which is illuminated when thebatteries are recharging.

This occurs whenever the power unit is connected to a 110 VAC line. Acharging circuit regulates the recharging process.

FIGS. 13 and 14 illustrate a holster 130 for accommodating the forceps10. A cavity 132 receives the tine end of the forceps 10. A loop 134 orslits 135, 136 may be provided for attaching the holster 130 to a belt140.

The foregoing discussion of the invention has been presented forpurposes of illustration and description. Further, the description isnot intended to limit the invention to the form disclosed herein.Consequently, variations and modification commensurate with the aboveteachings, and the skill or knowledge in the relevant art, are withinthe scope of the present invention. The embodiments described hereinabove are further intended to explain modes known of practicing theinvention and to enable others skilled in the art to utilize theinvention in such, or other embodiments and with various modificationrequired by their particular applications or uses of the invention. Itis intended that the appended claim be construed to include alternativeembodiments to the extent permitted by the prior art.

1. A method for thermocauterizing tissue, comprising the steps of:squeezably grippingly engaging tissue to be cauterized or a blood vesselto be sealed between tip portions of a thermocautery surgical forcepsincluding a pair of spaced and opposed tine members each having tipportions, each tip portion including a heater element with a flatgripping and heating surface; and activating the heater elements to heatthe flat gripping and heating surfaces thereof to tissue cauterizing orblood vessel sealing temperature and thereby applying substantiallyuniform pressure and heat to a tissue gripped between the gripping andheating surfaces.